The present invention relates generally to intermittent liquid dispersal and more particularly to intermittent liquid dispersal for irrigation and pest control.
A wide variety of irrigation systems are commercially available for use in watering crops, plants, and lawns. Sprinkler-based systems are generally the most popular, although systems that deposit water directly on the ground are also utilized, such as drip systems. In either case these systems are often automated so that they irrigate an associated area on a periodic basis without substantial human intervention.
Automated systems typically comprise an electronic controller and solenoid valve electrically coupled to the controller. The solenoid valve is typically located inline with a pressurized source of water. In operation, the valve opens to allow water to flow from the source, through a conduit, and out one or more sprinkler heads or drip emitters. When the cycle is complete, the controller signals the solenoid valve to close. Typically, these systems operate no more than a few times in day. A typical watering cycle may last anywhere from a few minutes to more than an hour.
After a watering cycle has been completed, it is not uncommon for the ground to be soaked and saturated. In the intervening period between cycles, the soil can become arid, especially in hot and dry climates. Both saturated and arid ground conditions can be damaging to certain types of plants. For instance, a seedling without a developed root system can be dislodged from the soil if enough water is added to the ground to cause puddling. Additionally, if the ground around a seedling is allowed to dry completely for even a short period of time the seedling can quickly dehydrate and die. Furthermore, there are types of plants that have root systems that are very intolerant of saturated soil conditions and can be damaged if exposed to saturated soil on a regular basis.
Ideally, it would be desirable to maintain soil at a predetermined and constant moisture level that is ideal for the plants growing therein. Increasing the frequency of irrigation cycles while reducing the time there between helps to maintain the soil at a more constant moisture level, but most electronic controllers are designed only to open an associated solenoid at most a few times every day. Even if controllers were available that allowed frequent watering cycles of short duration, the electronic solenoids generally available for use in sprinkler systems are not designed for continuous repetitive duty.
Another drawback of electronic systems is that they require coupling to an electrical power source that may not be conveniently available. Additionally, the conduits of electrical current, such as the wires between the solenoid and the controller, must be protected from moisture and other potential sources of damage. These requirements of traditional automatic systems make them complicated and consequently difficult and expensive to install.
Another problem that traditionally affects farmers and home gardeners alike is damage done to plants and crops by animals. It can be appreciated that animals in general will not bother plants or crops while a sprinkler is in operation because either they do not like the water or they are scared by sprinkler noise. Traditional sprinklers are relatively effective in deterring animals from entering an area being irrigated. Unfortunately, traditional sprinklers cannot be left on continuously for extended periods of time because of the amount of water used and the potential saturation of the underlying soil. Other objects, such as scarecrows, have very little effect on most animals. There are solutions that can be applied to the surfaces of plants that make them undesirable to animals, although the nature of the solutions often preclude there use on crops that are to be consumed by humans.
Various embodiments, presentations, and configurations of a valve for the intermittent distribution of a fluid according to the present invention is described herein. In one embodiment, the valve includes a valve housing defining an interior cavity and a valve member that is at least partially contained within the cavity. The fluid is in a reservoir capable of holding the fluid under pressure. An inlet port is provided to receive the fluid into the cavity of the valve housing and an outlet port is provided to permit the fluid to flow out of the cavity. The valve member is moveable within the cavity between a closed position and open position. In the closed position, the valve member blocks the flow of the liquid in the cavity between the inlet port and the outlet port. In the open position, the valve member permits the flow of the fluid between the inlet port and the outlet port. Additionally, a biasing mechanism is provided to control the movement of the valve member between the closed and open positions. In particular, the biasing mechanism provides (i) a retention force applied against the valve member to hold the valve member in the closed position when the valve member is in the closed position, and (ii) a biasing force encouraging the valve member into the closed position when the valve member is in the open position, the biasing force being less than the retention force, in one example.
In another embodiment, the valve housing defines a bore with the inlet port and the at least one outlet port extending through a wall of the housing from the bore. The inlet port is adapted for coupling to the source of liquid, and is in fluid communication with the at least one outlet port through the bore. The valve further includes a valve stem that is at least partially contained within the bore. The valve stem is movable between an open and closed position in the bore (the stroke), wherein the valve stem blocks the flow of liquid between the inlet and outlet ports in the closed position and permits the flow of liquid between the inlet and outlet ports in the open position. A biasing mechanism is provided that applies a retention force to hold the valve stem in the closed position within the bore when the valve stem is in the closed position. Additionally, the biasing mechanism provides a return force encouraging the valve stem into the closed position when the valve stem is in the open position, wherein the magnitude of the return force is less than the retention force. The stroke may be set by a retention strap or the like. In addition, the bore may define a second enlarged section of the bore, and the valve stem may include a stopper adapter to operate within the bore and thereby control the stroke.
In embodiments of the present invention, the biasing mechanism comprises two sets of one or more magnets, one coupled with the valve housing and the other with the valve stem. The retention force at least partially comprises the magnetic force between the magnets. Furthermore, the valve may include one or more O-rings that span the distance between the surface of the valve stem to the interior surface of the bore.
In other embodiments of the invention, a valve generally similar to those described above is utilized in conjunction with a reservoir designed to hold a fluid in a pressurized state. Operationally, the valve member moves into the open position from the closed position when the pressure in the reservoir exceeds a critical level, i.e., an activation force is equal to or exceeds the retention force. The valve member does not move back into the closed position from the open position until the pressure level in the reservoir drops to a second level that is less than the critical pressure level. Accordingly, a volume of liquid that is the difference between the volume of liquid contained within the reservoir at the critical pressure and the volume of liquid stored in the reservoir at the second pressure level is expelled from the reservoir through the periodic fluid release valve.
In another preferred embodiment, the reservoir is fluidly coupled to a pressurized source of liquid by way of a flow control regulator that controls the rate at which the reservoir is filled. A combination system including the regulator, the reservoir and the periodic control valve facilitates the repetitive cyclic release of liquid from the outlet port of the valve when a pressurized source of liquid is provided.
A fluid delivery system for periodic fluid dispersal and a method for the same are described herein. Embodiments of the present invention incorporate a pressure actuatable periodic fluid dispersion valve (periodic valve) as described below coupled with and located downstream from a reservoir containing a fluid. The reservoir is fluidly coupled with a fluid source with a flow regulator valve (regulator) intervening to control the flow rate of fluid from the fluid source.
In one embodiment, fluid flows into the reservoir from the source at a rate controlled by the regulator. The reservoir contains the fluid and expands as the volume of fluid in the reservoir increases. At a critical pressure, the periodic valve is triggered into an open position, wherein a portion of the fluid contained within the reservoir is expelled therefrom through the periodic valve. Once the pressure in the reservoir drops below a certain level that is generally lower than the critical pressure, the periodic valve closes.
In another method, the various embodiments of the valve are useful in forming a fire line to help prevent the movement of a fire passed a certain point. To form a fire line with the present invention, a plurality of sprinkler heads are distributed over an area of ground typically in a line. Each sprinkler head is fluidly coupled with the valve, and each valve is fluidly coupled with a reservoir. A source of fluid, such as water or other fire-line agents, is fluidly coupled with the reservoir so that the reservoir fills and the fluid therein is pressurized. The area of the ground in the broadest range of the sprinkler may then be kept at a level to reduce fire by the periodic dispersal of water from the periodic fluid dispersal valve assembly.
The operation of the periodic valve is in contrast to spring-loaded safety release valves that are commonly found on pressure vessels. Safety release valves open when a critical pressure is reached but close immediately once the pressure within an associated pressure vessel or reservoir decreases below the critical pressure. The volume of fluid released from a safety release valve is typically small, depending on the influx of fluid into the reservoir or pressure vessel from a pressurized source.
For purposes of illustration, the invention is described herein in terms of a periodic sprinkler for use in the irrigation of plants, lawns or crops and for use in forming a fire-line, as well as startling critters that may be after the crop. It is to be understood that other embodiments of the invention are contemplated for use wherever the periodic distribution of a fluid, liquid or gas, is required.